Re: Fwd: Postgres HA - pacemaker RA do not support auto failback - Mailing list pgsql-general

From Shital A
Subject Re: Fwd: Postgres HA - pacemaker RA do not support auto failback
Date
Msg-id CAMp7vw-cXr6B2fW_3AQoOFGoMrwGv-VK4RMK1=x9Zbz=SHcvrw@mail.gmail.com
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In response to Re: Fwd: Postgres HA - pacemaker RA do not support auto failback  (Adrien Nayrat <adrien.nayrat@anayrat.info>)
Responses Re: Fwd: Postgres HA - pacemaker RA do not support auto failback
List pgsql-general


On Mon, 12 Aug 2019, 18:54 Adrien Nayrat, <adrien.nayrat@anayrat.info> wrote:
On 8/12/19 2:57 PM, Shital A wrote:
>
>
> Hello,
>
> Postgres version : 9.6
> OS:Rhel 7.6
>
> We are working on HA setup for postgres cluster of two nodes in active-passive
> mode. 
>
> Installed: 
> Pacemaker 1.1.19
> Corosync 2.4.3
>
> The pacemaker agent with this installation doesn't support automatic failback.
> What I mean by that is explained below:
> 1. Cluster is setup like A - B with A as master. 
> 2. Kill services on A, node B will come up as master.
> 3. node A is ready to join the cluster, we have to delete the lock file it
> creates on any one of the node and execute the cleanup command to get the node
> back as standby
>
> Step 3 is manual so HA is not achieved in real sense. 
>
> Please help to check:
> 1. Is there any version of the resouce agent which supports automatic failback?
> To avoid generation of lock file and deleting it.
>
> 2. If there is no such support, what checks should be added in pgsql RA to achieve 
>
> Please suggest.
> Thanks.
>

Hello,

Which RA did you use? AFAIK there is two RA :
- pgsql : https://github.com/ClusterLabs/resource-agents/blob/master/heartbeat/pgsql
- PAF : http://clusterlabs.github.io/PAF/ (Which is different from pgsql RA :
http://clusterlabs.github.io/PAF/FAQ.html#why-new-ra-for-postgresql)

If I am right, PAF should handle the case when there no need to perform pgrewind
(if the old master is not too advanced in the transaction log).

Regards,

--
Adrien NAYRAT
https://blog.anayrat.info



Hello

We are using the pgsql RA installed with pacemaker. 

Is PAF recommended over pgsql?

Has anyone changed pgsql to handle the lock file and other cases that might not have been handled? 

Please advise.

Thanks.

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